1. Field of the Invention
This invention relates generally to an apparatus for reducing air pollution caused by solid particles and soluble gases in the fumes and exhausts from incinerators and industrial smoke stacks.
It is well known that fumes and exhausts coming from municipal incinerators, coal burning power stations and many chemical and metallurgical processing plants are major sources of air pollution. This is because they often contain contaminents such as soot resulting from incomplete combustion, fly ash and other solids, ammonia, cyanogen, hydrogen sulfide and the acid oxides of sulfur and nitrogen. The gases in addition to causing significant problems with their distinctive odors are, in sufficient concentrations, major health hazzards causing such problems as eye irriatation and respiratory illness and seriously aggravating cardiovascular illness. In addition the acid gases, on being hydrated by natural moisture, form an "acid" rain which is quite corrosive to many unprotected metals and marble stone structures. The solid particles in addition to causing major cleaning problems in many urban areas have been known to act as cloud seeds causing unexpected or excessive amounts of rain or snow to precipitate in regions downstream from the stack.
As a result of all this, there has been a significant effort made to greatly reduce, if not eliminate, all solid and soluble gas contamination in these exhausts. Over the years a number of devices have been developed for this purpose. For gas extraction, however, the most efficient methods require packed towers and careful control of both the physical and thermodynamic parameters for maximum efficiency. Thus, where large volumes of dilute gas such as incinerator exhausts are encountered, such devices are prohibitively expensive and, because of the significant solids content in the gas, loose their effectiveness quite rapidly.
Most devices for the removal of solids are primarily designed to remove dusts and mists having sizes down to approximately 0.1 micron. Here, too, there are a number of specialized systems which are effective but these carry the problems of requiring frequent cleaning if efficiency is not to be impaired and, of course, they are completely ineffective with gaseous contamination.